Rye Cheddar Feta Sourdough Batard

Steps

1. Day 1, morning: feed your sourdough starter its usual equal-weight feeding (separate from this recipe's ingredients) and leave it at about 75°F (24°C) for 4 to 6 hours, until doubled, domed and bubbly; at that peak, weigh out the sourdough starter for the dough.
2. Prepare the add-ins while the starter rises: cube the cheddar and crumble the feta, then keep both in the fridge so they stay in distinct pockets.
3. In a large bowl, whisk the water and the sourdough starter until milky.
4. Add the bread flour and 290 g of the rye flour (keep the remaining 10 g of rye flour for dusting), then stir with a stiff spatula or wet hand until no dry patches remain. The dough will be sticky and paste-like. Cover and rest 30 minutes.
5. Sprinkle the salt and black pepper over the dough and squeeze them in with a wet hand until evenly mixed.
6. Bulk rise at about 75°F (24°C) for 3 1/2 to 4 hours. During the first 2 hours, do 3 sets of stretch-and-folds 30 minutes apart, wetting your hands each time; rye dough won't stretch far, so lift and fold each side gently over the middle.
7. At the second set of stretch-and-folds, scatter the cheddar and the feta over the dough and fold them in until evenly spread. Leave the dough covered for the rest of the bulk rise, until it has grown by about half and shows bubbles on the surface and sides.
8. Dust a work surface and a parchment-lined loaf-shaped basket or bowl with half of the reserved rye flour. With wet hands, turn out the dough, pat it into a rectangle, roll it up tightly into a batard, and place it seam side up in the basket.
9. Dust the top with the remaining half of the reserved rye flour, cover, and cold proof in the fridge for 12 to 16 hours overnight; the loaf is ready when it has puffed slightly and fine cracks show in the rye dusting.
10. Day 2: place a lidded Dutch oven in the oven and preheat to 475°F (245°C) for 45 minutes.
11. Turn the cold batard onto parchment seam side down, score one long cut down its length, and lower it into the hot Dutch oven on the parchment.
12. Cover and bake 20 minutes, then remove the lid, reduce to 450°F (230°C) and bake 25 to 30 minutes more, until the crust is deep mahogany brown and the center reads 205°F (96°C). This dough is about 78% hydration and 1.6% salt, counting the rye flour, bread flour and water, plus the water and grain in the starter.
13. Cool the loaf on a rack for at least 3 hours before slicing into 12 slices; rye needs this time to set, or the crumb will be gummy.